SE431851B - VEXELINDIKERINGSANORDNING - Google Patents

Abstract

An indicator panel 20 has an array of LED's 25A to 25Q to provide an indication to the driver of a road vehicle, particularly a diesel-powered truck, when he should change to the next highest gear during acceleration from rest or low speed. The LED's are lit progressively as the engine speed increases in each gear and, when lit, emit green light if the engine speed is below the optimum change-up speed for that gear. When the engine speed begins to exceed the optimum change-up speed, the next LED illuminated produces red light to the driver. An audible warning may also be produced. If the driver does not change up in response to such warning, further red LED's will show and a more strident audible warning may be given. The change-up speeds to which the system responds are pre-set so as to be the optimum speeds for increased fuel efficiency. The change-up speed corresponding to the lowest gear is relatively low and increases successively for the successively high gears. The system may be associated with engine speed control or limiting means so as positively to prevent further increase in engine speed if the driver ignores the warning. The system may also produce an indication of the optimum engine speeds at which the driver should change down to the next lower gear during vehicle deceleration.

Description

820724141 2 of the activated light sources emitted the indication when the actual speed of the motor reaches the speed represented by the reference signal.

According to the invention, indicating means are also provided for identifying the gear ratio currently prevailing in a power transmission with a plurality of selectable, determined gear ratios, which indicating means comprises first conversion means operative to provide a first signal proportional to the input speed of the power transmission. second conversion means operative to provide a second signal proportional to the output speed of the power transmission, and signal processing means operative to measure the ratio of the first and second signals to indicate the identity of the prevailing gear ratio.

An electrical device which is an embodiment of the invention and which has the task of indicating to the driver of a road vehicle when he should perform each shift for best efficiency will now be described, by way of example only, with reference to the accompanying schematic drawings. , in which Fig. 1 shows a block diagram of an embodiment of the device, Fig. 2 is a front view of an indicator panel, which view schematically shows the indication given to the driver, and Fig. 3 is a more detailed block diagram of the device.

The device which will be described is specially designed to give an indication to the driver of a diesel-powered truck when he should shift. Large, powerful diesel engines, especially of the self-priming type, provide maximum torque at a relatively low engine speed, and it is therefore inefficient for the driver and also a waste of fuel to run the engine at a speed above the top of the torque curve when the vehicle does not need or can drive at high speed. It is especially true that when the truck is started from a standstill, it means a waste of fuel if the driver revs up the engine to high speed in low gear. When starting a truck from a standstill, the primary requirement with regard to the low gears is that the engine speed must be increased to the speed at which maximum torque is obtained. As the speed of the truck increases and as each higher gear is engaged, the engine speed may be increased gradually immediately before the change in question, assuming that the desired final road speed with the highest gear corresponds to an engine speed higher than the value at which the maximum torque is obtained. 820724141, 3 For maximum efficiency when starting a truck from a standstill, in other words, the driver should each time in turn shift at a successively higher speed of the engine. The device that will be described facilitates this.

Fig. 1 shows the device very generally. As can be seen from said figure, the device 5 comprises a unit 5 for detecting engaged gear. The purpose of the unit 5 is to generate on a line 6 an output signal which identifies the current gear via which the truck engine is driving the road wheels at a certain time (ie the output signal represents the total gear ratio between the truck engine and the road wheels). The unit 5 receives a suitable input signal on a line 8. The line 8 could, for example, be controlled by means of micro-switches depending on the setting positions of the driver's gear control levers. However, other means of generating the signal on line 8 will be described below.

The gear indicating signal on line 6 is fed as an input to a data memory 10. The memory 10 stores a number of different reference signals, a different one for each of the truck's gears.

The value of each reference signal represents the optimum engine speed at which the driver should shift from the internal gear to the next higher gear, ie the speed is "optimal" primarily from the point of view of promoting maximum fuel efficiency. Thus, as explained above, the reference signal corresponding to the lowest gear will represent a relatively low speed of the motor, while the reference signals of the higher gears will represent successively higher speed values of the motor. The memory 10 responds to the current exchange which is marked by the signal on the line 6 by said memory outputting the intended reference signal on a line 12, the signal in question being input to a signal processing unit 14. The unit 14 also receives a signal which represents the actual speed of the engine on line 16, and it emits on line 18 an output signal which controls an indicator unit 20 for the driver. The unit 20 is positioned in such a way that the driver can easily react to its indication. The unit 20 can give its indication in any suitable form. This indication may, for example, be visible, or instead it may be audible. As another example, it could be a combination of visible and audible indications.

The signal processing unit 14 controls the indicating unit in such a way that it gives the driver an indication when the truck's engine speed with a certain gear engaged has reached the value where he should switch to the next higher gear.

When the driver has shifted to the next higher gear, the signal processing unit 14 receives the new reference signal on line 12, and it can thus control the indicating unit 20 in such a way that it gives an indication when the actual speed of the motor has risen to the (higher) motor speed reference where he should gear up again ..

As will be described in more detail below, the signal processing unit 14 may also be designed by means of a suitable speed control device or speed limiting device to set a definite limit on the engine speed if the driver does not care about the indication given by the unit 20 that he should shift.

A particular design which the device according to Fig. 1 can assume will now be described in detail with reference to Figs. 2 and 3.

Fig. 2 shows a design that the driver's indicator 20 (compare Fig. 1) can assume. It comprises a group of lamps 25A, 25B ..... 250.

In this example, there are thus seventeen lamps, each corresponding to an increase of 50 revolutions per minute in the engine speed. The lamps can cover a speed range from, for example, 1,000 to 1.80o revolutions per minute. As the motor speed increases, the lamps will light up in turn, starting with the lamp 25A. Thus, when the engine speed rises to 1,000 rpm, the lamp 25A lights up. An increase in the engine speed to 1,050 revolutions per minute means that the lamp 25B is lit, the lamp 25A remaining lit, etc. until at the engine speed 1,800 revolutions per minute all the lamps are lit.

In a way that will be described in more detail, the colors that the lit lamps have change so that the driver is informed when to change each time.

The lamps 25A - 25Q are physically arranged in a curve which approximately corresponds to the shape of the engine torque curve plotted against engine speed within the current speed range (the example shown showing that the maximum torque occurs at about 1,500 rpm per minute). The lamps used can be light emitting diodes (LEDs).

The device will now be described in more detail with reference to Fig. 3.

As shown in Fig. 3, the device is activated by transducers 50 and 32, the converter 50 giving rise to an electrical output signal on a line 54 representing the motor speed (motor speed) and the converter 32 giving rise to an electrical output signal on a line 56 representing the path speed (vehicle speed 8207241-4 on the road). The transducers 30 and 32 may be of any suitable type. For example, the engine speed converter 30 can sense an electrical signal from the driver's engine speed indicator, while the road speed converter may sense an electrical signal from the vehicle's tachograph. However, other arrangements are also possible. The electrical output signals on lines 34 and 36 may be in analog form or digital form.

Lines 34 and 36 are connected to a crossover circuit 38 which measures the ratio of the signals on the lines. This ratio depends only on the particular gear engaged, and the divider circuit 38 compares the measured ratio with each of a number of pre-stored reference values equal to each of the ratios corresponding to the gears, after which the divider circuit emits on a line 40 an electrical output signal which indicates which gear is in at a certain time.

It should be emphasized that the signal on line 40 could instead be generated by, for example, an electromechanical switch device interconnected with the gearbox or with the gear selector. However, the device shown in more detail in Fig. 3 has the advantage that it is simple and has no moving parts.

Regardless of how the signal on line 40 is generated, it is fed into a memory 42 after generation. This can take any suitable shape and stores a series of electrical reference signals corresponding to different gears of the truck. The reference signal stored in memory 42 for the first gear has the lowest value, and the values become successively larger (but not necessarily in linear proportion) for each of the successively higher gears.

The memory 42 makes the intended reference signal accessible, i.e. the reference signal corresponding to the particular gear which is loaded (as indicated by the value of the signal on line 40) and outputs this reference signal on line 44. Said signal is passed on a line 46 to a treatment center 48.

The processing unit 48 includes a group of output lines 52A, 52B ..... 52Q (not all of which are shown), and these lines are connected to separate level change units 54A, 54B ..... 54Q (of which not all are shown ). The connections that exist in reality are for the most part omitted so that the schedule is not complicated unnecessarily.

The outputs of the level change units 54A, 54B ..... 54Q are via their respective lines 55A, 553 ..... 55Q connected for control of each 8207241-4 of the lamps 25A, 25B ..... 250 in the driver's table 20 .

The processing unit 48 activates the lines 52A, 52B ..... 52Q in accordance with the value of the signal on the line 46, each line 52A, 52B ..... 520 having either a high value or a low value. When the signal level on line 46 is low, only the previous line or lines in succession lines 52A - 52Q will be kept at the low level while all the others will be high. For example, when the signal on line 46 has its lowest level (corresponding to the first switch), only, for example, lines 52A and 52B will be at a low level while all the others are at a high level. For a signal level on line 46 corresponding to the second exchange, several of the lines in groups 52A - 520 would be at a low level, for example lines 52A, 52B, 520 and 52D, while all others would be at a high level. This thus applies to all the other conceivable values of the signal on line 46. For a signal level on line 46 corresponding to the highest gear (for example, the truck may have eight or nine gears) all lines 52A - 520 could be at the low gear level.

The motor speed dependent signal on line 54 is also connected in such a way that it feeds a group of comparators 64A, 64B ..... 64Q (of which only a part is shown). Each comparator has a second input line which transmits its own threshold signal (the sources of these signals are not shown in the figure). The comparators 64A - 640 are connected through the level change units 54A - 54Q to the light emitting diodes via their respective output lines 66A - 660. When the motor speed is low (at a speed of less than 1,000 rpm in this example), none of the lines 66A - 66Q are activated.

As the engine speed increases to 1,000 revolutions per minute and beyond this value, lines 66A - 660 are gradually activated.

The threshold signals applied to comparators 64A - 640 are set so that line 66A is activated when the engine speed is 1,000 rpm, line 66B is activated when the engine speed reaches 1,050 rpm, line 66C is activated when the engine speed reaches 11100 rpm, etc., until line 660 becomes activated when the engine speed reaches 1,800 rpm (all previously activated lines remain activated).

As each of the lines 66A'-660 becomes activated, it causes the corresponding light emitting diode 25A-250 to light up. Assuming that the corresponding wire among the wires 52A - 52Q is at a low level, it emits the lit light. * ice 7 emitting diode green light. However, if the corresponding line 52A - 52Q is at a high level, the corresponding level change unit 54A - BÄQ will cause the lit light emitting diode to emit a red light instead.

The working method of the facility as far as it has been described so far will now be considered.

When the truck starts from a standstill with the first gear engaged, the engine speed is below 100 000 revolutions per minute, so that none of the lines 66A - 66Q are activated. Therefore, none of the light emitting diodes 25A - 25Q will be lit either. The crossover circuit 38 determines from the relationship between its input signals that the first gear is engaged, so that the memory 42 emits an intended reference output signal. As has been explained, this signal has such a value that the unit 48 keeps most of its output lines 52A - 52Q at the high level, with only the lines 52A and 52B (in this example) being at the low level.

As the engine speed increases to 1000 rpm (with the truck's first gear still engaged), line 66A is activated, igniting the light emitting diode 25A. Since the corresponding level change unit 54A receives only a low level, the line 66A will be activated at a low level, the light emitting diode 25A emitting green light.

As the motor speed continues to increase, the light emitting diode 25B is turned on, which emits a green light (since in this example it is assumed that the line 52B is at a low level).

However, line 52C and all remaining lines up to line 52Q are at a high level. Thus, when the motor speed in this example reaches the value of 1,100 revolutions per minute, the light emitting diode 250 is lit, emitting a red light in contrast to the light emitting diodes 25A and 25B, which emit a green light.

This gives the driver an indication that he has reached a value of the engine speed, which in the case of the particular gear in front of the eyes (the first gear) is such that he should shift to the next higher gear.

If he does not shift, the motor speed will continue to increase, whereby the light emitting diode 25D lights up and emits a red light, which also applies to the light emitting diode 25E if he still does not change.

If, on the other hand, he switches, this is detected by the divider circuit åååfläzovzëiíll-a i i 8 38, whereby the memory 42 changes the value of the signal on the line 46 to a higher value. This causes the processing unit 48 to change the activation of the lines 52A - 52Q in such a way that, for example, the lines 52A, 52B, 52C and 52D are all at a low level while the others (52E - 52Q) are at a high level.

The light emitting diode 25C, which previously emits a red light, will thus now switch to emitting a green light, assuming that the motor speed still has a speed of 1000 (the motor speed can obviously decrease slightly during the actual shift, but it then starts to rise again when it higher gear is engaged).

When the motor speed has reached the appropriate limit for the second gear, 1.25 ONarv per minute in this example, the light emitting diode 25E lights up, emitting a red light. This indicates to the driver that he must change gears again.

The process described continues for each subsequent gear, and Table 20 thus indicates to the driver the appropriate engine speed at which he should shift each time.

The reference signals in the memory 42 are preselected in such a way that the indicated speeds for shifting increase gradually and in accordance with a suitable curve so as to obtain maximum fuel efficiency from the engine.

As shown, lines 55A - 55Q are also connected to a counting unit 70 by level actuators 72A, 7215. . . . . 72Q, of which only some are shown. The level sensitive units are set so that the counting unit is only affected by signals on lines 52A - 52Q when they have their higher levels corresponding to the emission of red light from the corresponding light emitting diode. The counting unit or counter 70 counts the number of lines 55A - 55Q which have red generating levels and drives a unit 74 for an audible warning sound accordingly. More specifically, when the counter 70 detects a line 55A - 55Q having a red indicating level, it causes the warning sound unit 74 to issue an intermittent low frequency audible warning to the driver, thereby notifying him that the switching limit has been reached. If the driver does not shift, as described above, the next line among lines 55A - 55Q will change to a red indicator level. This is detected by the counter 70 which causes the warning unit 74 to increase the frequency of its output sound. A further increase in the engine speed without shifting, whereby a third red-indicating level input signal to the counter 70 is obtained, causes the unit 74 to emit a continuous output noise. The truck may also be provided with a road speed control device, which device is schematically shown by block 80. Such a device may be designed in any suitable manner, for example in the manner described in the British Patents. 1 586 961 and l Ä9} 625. Such a device 80 normally operates only when the truck has its highest gear engaged, thereby limiting the road speed of the truck to a certain upper speed value (or regulating the speed at this value), this operation being independent of the device for indicating shifting as far as this device has been described so far. However, the described device for indicating shifting can be linked to the speed control device 80 by means of a line 84 from the counter 70.

The counter 70 activates line 84 when it determines that at least three of lines 55A - 55Q have red indicating levels. When the speed control device 80 receives the signal on the line 8Ä, it operates (regardless of which gear is currently engaged) in such a way that it prevents the motor speed from increasing further.

Thus, if the driver continues to disregard the gearshift indication given by Table 20, a further increase in engine speed will be forcibly prevented. A As far as has been described so far, the operation of the gear indicating device is the operation which occurs when the truck is accelerating. The operation will be different if the vehicle is decelerated, as will now be described.

The deceleration of the truck is sensed by means of a differentiating unit 90 which can be actuated depending on the road speed signal on the line 36. If the vehicle decelerates at at least a predetermined rate represented by a threshold value on a line 92, a comparator 9Ä activates a line 96 so that a gate 98 opens.

In addition to providing the reference signal on line 46, the memory 42 produces a second reference signal on line 100. In contrast to the reference signals on line Ä6, the reference signals on line 100 represent the minimum suitable motor speed corresponding to each gear. The line 100 is connected via the gate 98 to a comparator 101 which also receives the signal originating from the line 34 which indicates the motor speed. Gate 98 does not transmit the signal on line 96 to comparator 101 except when the truck is decelerated at least at the speed indicated by the threshold value on line 94. Comparator l01 has output lines l02A - l02K, which are connected to third inputs to level change 820? 2l + 1-læ 10 the units 52A - 52K, the connections themselves having been omitted in the figure. When the comparator 101 determines that the actual speed of the motor has dropped to the level represented by the reference signal on the line 100, it activates the corresponding output line l02A - l02K and all the others among its output lines which represent lower speed values. Thus, for example, if the signal on line 100 represents a reference speed corresponding to 1,400 revolutions per minute, the comparator 101 activates its output line 102I (which is connected to the level change unit 541 which controls the light emitting diode 25I representing 1,400 revolutions per minute). In addition, it activates all wires l02A - l02H.

The operation of this part of the device will now be described in more detail.

If the truck is running at a constant, relatively high speed with the highest gear and its engine speed is higher than 1,800 rpm, all the light emitting diodes 25A - 25Q will turn green. If the speed of the truck now decreases, which as a result leads to a corresponding reduction in the engine speed, the light emitting diodes will be switched off one at a time as the engine speed drops below 1,800 rpm. Assuming that the speed of the truck decreases at a faster rate than the threshold rate represented by the signal on line 92, the unit 94 will open gate 98, the comparator 110 being fed with the reference signal on line 100, which signal represents the appropriate minimum speed. for the current gear (highest gear). This could, for example, correspond to an engine speed of 1,400 rpm. Thus, when the comparator 101 determines that the actual speed of the engine has dropped to 1,400 revolutions per minute, it activates the lines 102A - 102I. The resulting signals supplied to the level change units 54A - 54I cause the corresponding light emitting diodes 25A - 2 251 to change their color from green to red. This thus entails an indication to the driver that he should switch to a lower gear.

If the driver allows the motor speed to drop further without shifting, the dropping signal on line 62 will cause comparators 64A - 64I (in this example) to turn off the light emitting diodes one at a time.

During this deceleration, the unit 74 for an audible warning may be disconnected.

It should be noted that the detailed circuit azovzafëa ll shown in Fig. 3 is only an example of many different conceivable forms that can be used, so many modifications are possible. As a non-limiting example, it may be mentioned that the interconnection of the gear indication device with the speed error device 80 may be omitted and / or that the devices may be such that the indication given to the driver when he is to shift to a lower gear may be omitted.

Although the devices described above have been tested in connection with lorries and more particularly with lorries powered by diesel engines, they may be applied (with appropriate modification if necessary) to vehicles other than lorries and to vehicles powered by other types of engines, and the term "vehicle" is not limited to road vehicles. For example, it may include rail-bound vehicles and boats.

Claims (9)

82Û72l + 1 '-4 12 PATENTKRAV An indicator device for use in a mechanically driven vehicle with a driver-actuated system for power transmission from the engine to a drive wheel and with several gears, which indicator device shall indicate to the driver when he should shift to a higher gear and comprises a means (8) for sensing which gear is engaged at any time to generate a reference signal with a value representing a reference speed bit depending on the identity of the gear in question, a shift indicator (20) to give an indication to the driver when he should shift to the next higher gear, a means (16) which senses the real speed and thereby generates a signal indicating the real speed, and a monitoring means (14) which is switched on to receive and compare the reference signal and the signal indicating the real speed in order to thereby causing the indicator (20) to generate an indication that the driver should shift to the next higher gear when the actual speed reaches the reference speed, recognizing that the driver's indicator (20) can generate any of a plurality of series of gear change indications (54A-54Q) indicating to the driver with successive urgency that he should shift to the next higher gear and that the monitoring means (14) is arranged to generate the first indication in said series when the actual speed reaches the reference speed and to generate in turn the other indications in said series if the driver does not shift to the higher gear and the the actual speed exceeds the reference speed to a predetermined extent or to a predetermined extent. Device according to claim 1, characterized in that the reference speed for the lowest gear represents a relatively low engine speed and that the reference speeds for the higher gears represent successively higher engine speeds. Device according to claim 1 or 2, characterized in that each of said indications is an audible indication. 8f2Û? 2-'ïs1 ~ 1 + 13 Device according to any one of claims 1-3, characterized in that each of said indications comprises a visible indication (25A ~ 25Q). Device according to any one of claims 1-4, characterized in that the monitoring means (14) includes a means (101) which is operative when the speed of the vehicle decreases and which is switched on to respond to said reference signal and on said signal indicating the actual speed to cause the indicator (20) to generate the first indication in a second series of indications when the actual speed has dropped to a value at which the driver should shift to a lower gear and to generate in turn and order the other indications in the second series cm the driver does not shift to the lower gear and the actual speed drops below the speed at which he should have shifted to the lower gear. Device according to any one of claims 1-5 in combination with a means (80) for monitoring or limiting the speed of a vehicle, characterized by a means (84) which is operative in response to the actual speed exceeding the respective the reference speed of the gear which is in fact engaged to a predetermined extent in order to forcibly prevent a further increase in the vehicle speed. Device according to any one of claims 1 ~ 6, characterized in that said actual speed is the engine speed. Device according to one of Claims 1 to 7, characterized in that the indicator (20) comprises a series of light sources and that marking of successively greater urgency in each indication is effected by changing the color of the light emitted by each light source. Device according to claim 8, characterized in that the series of light sources (25A-25Q) are physically arranged in a manner which corresponds substantially to the shape of the torque curve plotted against the motor speed of the motor.